Typing != Complexity
Developers of all experience levels commonly share a false belief: more typing means more complexity. The most powerful idioms and tools often require a few extra keystrokes, but dramatically reduce complexity. The final keyword in Java is a bit of extra typing. The final keyword can be applied to variables, method parameters, instance members, static members, methods, and classes. By making these final, their values will not depend on their context. They will be known constants through their lifetime. Their constancy removes a large cognitive load. The developer no longer needs to worry if the value was not set or if it was set multiple times. Many developers forgo this benefits to avoid typing the extra keyword, to their own detriment. Later, they spend too much time chasing down defects caused by mutable state. Developers will often shun creating small types and interfaces because of the extra typing involved. Interfaces can abstract away many different implementations behind